Device for feeding an additive to a melt



G. KPKE ET AL DEVICE FOR FEEDING AN ADDITIVE To A MELT `Ian. 20, 1959 Filed July 2l,

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United States Patent O DEVlCE FOR FEEDING AN ADDITIVE T A MELT Gnter Kpke, and Kurt Ulbricht, Oberhausen-Sterlrrade, Germany, assignors to Gutehoffnimgshiitte Sterkrade Aktiengeselischaft, Oberhausen-Sterlrrade, Germany Application July 21, 1955, Serial No. 523,407

Claims priority, application Germany July 24, 1954 6 Claims. (Cl. 266--34) tive to iron, particularly in the production of cast iron.V

The evaporation temperature of magnesium, however, is considerably lower than the melting temperature of iron so that the magnesium tends to evaporate in the form of an explosion when it contacts the iron melt and 4thus causes a violent agitation of themelt.

Numerous suggestions have been made to prevent the evaporation of the magnesium in the form of an explosi-on as it enters the bath. It has been found essential to introduce the magnesium as deeply as possible below the bath level. The higher the static pressure of liquid iron above the point where the magnesium is introduced the more strongly will the evaporation of the magnesium be suppressed.

For this reason the magnesium has been introduced into the bath in most cases only after the ladle had been completely Ifilled with the melt. This required the use of relative large melts. In the case of fluctuations in the manufacturing program, however, there may be cases where only small quantities of iron are to be treated at a time.

Besides, for the sake of uninterrupted operation, the treatment 0f cast iron should take place immediately after it has been tapped from the cupola. Previously the treatment had to be suspended until the iron tapped from the cupola had filled a ladle. The -illing of a large ladle, however, takes a considerable period of time, during which the operation is interrupted and the temperature ofthe iron melt is reduced. That temperature drop is continued during the subsequent treatment of the melt with magnesium. As a result the spherulitic iron obtained by the treatment may be too viscous to be poured.

It is desired, therefore, to begin the feeding of the magnesium only a short time after the charging of the ladle withiron has begun, in order to utilize the charging time also for the treatment itself and thus to avoid an eX cessive cooling of the melt until it is poured. At the same time the feeding of the magnesium must be performed in such a manner that the evaporation of the magnesium will not cause an excessive agitation of the bath even in the early phase of the charging operation, when the iron has only a low static pressure.

It is an object of the invention to provide a device for suppressing the agitation caused in a melt when fed at or near its surface with an additive tending to form vapor when contacting said melt.

2,869,857 valientes Jan. zo, 1959 It is another object of the invention to provide a device for feeding a melt with an additive tending to form vapor when contacting said melt, which device permits of beginning the feeding of said additive into afmelt vessel only partly lled with said melt Without causing undue agitation of the latter.

.it is another object of the invention to provide a device for feeding a melt with an additive tending to form vapor when contacting said melt, which device permits Vof feeding said additive to said melt during a major portion of the period in which said melt is being charged into a melt vessel.

It is another object of the invention to provide a device for feeding a melt with an additive tending to form vapor when contacting said melt, which device substantially avoids an introduction of said additive into said melt in other than vaporous form.

With these and other objects in mind, which will become apparent as the specification proceeds, the invention provides a device for feeding an additive into a melt, comprising a chamber member having a closed top and a side wall, a partition dividing the interior of said chamber member into a feed chamber and a vapor escape chamber, said chambers being open at their lower end and communicating with each other at the top of said chamber member, said partition extending downwardly beyond the lower end of said side wall, and inlet means arranged to feed said additive directly to said feed chamber.

Two illustrative embodiments of the invention are shown diagrammatically in the drawing.

The overall arrangement shown in both figures comprises a melting furnace 1 for the iron to be treated and a ladle 4 movable by means of a car 3 and adapted to be charged through the spout 2 of the furnace 1.

According to Fig. '1 the feeding device of the invention comprises a chamber member 6 having a closed top and a refractory-lined annular cylindrical side wall, which is slightly immersed in the iron bath 7 in the ladle. 'An annular cylindrical partition 8, which is concentric with Athe side wall of the chamber member 6, divides the interior of the member 6 into a feed chamber anda vapor escape chamber. Both said chambers are open at their lower end. The partition 8 extends downwardly into the iron bath beyond the lower end of the side wall of the chamber member 6. The upper end of the partition 8 does not extend as far as to the top of the chamber mem# ber 6 so that the feed chamber and the vapor escape charnber communicate with each other at the top of the cham.- ber member 6. The partition 8 is connected to the chamber member 6 by suitable means (not shown).

Inlet means are provided to feed the magnesium or another additivedirectly to the feed chamber. According to Fig. 1 said inlet means comprises a vertical feed tube 5, whose lower end is disposed on the vertical center line of and carries the chamber member 6 and opens into the interior of said chamber member directly above the feed chamber. The tube 5 is vertically adjustable relative to the ladle 4.

When the level of the iron melt has reached the lower rim of the partition 8 during the charging of the ladle 4, the magnesium or another additive, preferably in liquid form, is fed under pressure at a controlled rate through the tube 5 from above into the ladle. The magnesium will begin to evaporate immediately as it contacts the melt in the Afeed chamber. The vapor collecting in the feed chamber is unable to rise into the tube S againstthe presisure of the inowing liquid magnesium and passes over at the top of the chamber member 6 into the vapor escape chamber, in which it is downwardly deflected by the side wall of the chamber member 6 and can escape at this time between the lower rim of the side wall and the bath level. This escaping magnesium reacts to some extent with the liquid iron on the surface of the bath. rEhe proper feeding of the additive can bechecked without appreciable loss or other undesired results because it is indicated by the freely escaping, ame-formingmagnesium vapor.

Shortly thereafter the bath level reaches the lower rim of the side wall of the chamber member 6 so that the lower end ofthe chamber member is entirely closed. rhe magnesium vapor must now penetrate the melt. lt escapes from the chamber member again at the lower rim of its side wall because the static pressure to be overcome is lower there than at the lower rim of the partition 8 (cf. the arrows in Fig. l). As the treatment is continued the reaction conditions, which are apparent from the bubbling on the bath surface, may be controlled by varying the feed pressure of the magnesium and/or the height of the feed tube in adaptation to the rising bath level, which would cause an increase in the static pressure if the feed tube were maintained at the same height.

According to Fig. 2 the feeding device of the invention in irmly incorporated in the ladle or melt vesselY 4. lt comprises again a chamber member 10, which has a closed top and a-side wall, both of which are carried by and sealed to the lower part of the peripheral wall of the ladle 4. Thus the interior of the chamber mrneber 10 is partly confined by a portion of the peripheral wall of the ladle 4. A partition 11 is provided, which divides' the interior of the'chamber member 10 into a feed chamber adjoining the peripheral wall of the ladle 6 and a vapor escape chamber. Both said chambers are again open at their lower end. The partition 11 extends downwardly beyond `the lower end of the side wall of the chamber member it?. The upper end of the'partition 8 does not extend as far as to the top of the chamber member 10 so that the feed chamber and vapor escape chamber communicate with each other at-the top of the chamber member 1t). The partition 11 may be connected to the peripheral wall of the ladle 4 or to the chamber member 1b by suitable means (not shown).

According to Fig. 2 the inlet means for feeding the additive directly to -the feed chamber comprise a tube 9,' which extends through the peripheral wall of the ladle 4 where it adjoins the feed chamber and opens into the latter.

The feeding. of the magnesium or other additive begins again when the ylevel of the iron melt has reached the lower rim .of thepartition l1 as the ladle is being charged. At this time the magnesium vapor formed may expand and'escape below the side wall, which is not yet immersed l in the melt. When the bath level has risen sufficiently to close the lower end of the chamber member 1l entirely, the agitation of the bath will be suppressed by the static pressure ofthe bath at the point where the vapor escapes. In this embodiment a control is possible only by a variation of the feed pressure of the magnesium.

The device according to the invention enables the magnesium to'be fed at an early phase of the charging of the ladle already and ensures that the additive is utilized in a high degree and favorable manner for the treatment of the iron melt. In this connection it is important that the portion of the bath surface which is particularly highly agitated by the evaporation of the magnesium is c ontained in the Aclosed-topped.chamber member and the magnesium escapesin the form of vapor from the chamber member into the bath.

What is claimed is:

1. A device for feeding an additive intora melt, comprising a chamber member having a closed top and aside Wall, a partition dividing the interior of said chamber member into a feed chamber and a vapor escape @hallabanY said chambers being open at their lower end and com municating with each other at the top of said chamber member, said parti-tion extending downwardly beyond the lower end of said side wall, and inlet means in direct communication with said feed chamber.

2. A device for feeding an additive into a melt, comprising a chamber member having a closed top and a side wall, a partition dividing the interior of said chamber member into a feed chamber and a vapor escape chamber, said chambers being open at their lower end and communicating with each other at the top of said chamber member, said partition extending downwardly beyond the lower end of said side wall, and inlet means comprising a feed tube having a lower end carrying said chamber member and opening into theV interior of said chamber member directly above said feed chamber to feed said additive directly thereto.

3. A device for feeding an additive into a melt, comprising a chamber member having a closed top and an annular side wall, an annular partition which is concentric with said side wail and divides the interior of said chamber member into a feed chamber and a vapor escape chamber, said chambers being open at their lower end and communicating with each other at the top of said chamber member, said partition extending downwardly beyond Vthe lower end of said side wall, and inlet means comprising a feed tube having a lower end carrying said chamber member directly above said feed chamber to feed said additive directly thereto, said lower end of said tube being disposed on the vertical center line of said chamber member.

4. A device for feeding an additive into a melt contained in a melt vessel formed with a peripheral wall, said device comprising a chamber member having a closed top and a-side wall both of which are laterally sealed to the inside of the lower part of said peripheral wall, a partition dividing the interior of said chamber member into a feed chamber adjoining said peripheral wall and a vapor escape chamber, said chambers being open at their lower ends and communicating with each other at the top of said chamber member, said partition extending downwardly beyond the lower end of said side wall, and

. inlet means extending through said peripheral wall where it adjoins said feed chamber and opening into said feed chamber to feed said additive directly thereto.

5. A device for feeding an additive into a melt, comprising a chamber member having a closed top and a side wall,

a partition dividing the interior of said chamber member into a feed chamber and a vapor escape chamber, said chambers being open at their lower end and communicating with each other at the top of said chamber member, said partition extending downwardly beyond the lower end of said side wall, inlet means in direct communication with said feed chamber, and means operatively associated with said chamber member for raising and lowering the same relative to the liquid level of the melt.

6. In an arrangement of the character described, in combination, first conduit means having a spout portion adapted to be immersed into a liquid to be treated, said spout portion being so constructed and arranged that a liquid treating medium ilowing through said rst conduit means into the liquid to be treated traverses but a portion of the cross-section of said spout portion; and second conduit means having one end portion in communication with the remainder of the cross-section of said spout portion of said rst conduit means, said second conduit means being so constructed and arrangedthat its other lend portion projects justbelow the surfacel of the liquid to be treated when said spout portion of said rst conduit means is immersed therein, whereby when said spout portion of said rst conduit means is immersed in a first metal in liquid state andsa'id other end portion of said second conduit means projects below the surface of the liquid first metal and when a stream of second metal having a boiling point substantially lower than the melting point of the first metal is passed in liquid state through said lirst conduit means, said stream ows through but said portion of the cross-section of said spout portion and yis vaporized upon contact with said liquid first metal, whereupon the thus-vaporized second metal iiows through said remainder of the cross-section of said spout portion and through said second conduit means so as to be introduced into said first liquid metal just below the surface thereof.

References Cited in the tile of this patent UNITED STATES PATENTS Burr Sept. 9, 1919 Williams Aug. 8, 1933 Gilbert Dec. 23, 1941 Wade June 17, 1952 Zifferer Feb. 5, 1957 Harrison May 28, 1957 FOREIGN PATENTS Austria Mar. 25, 1953 

